Aptitude - Ratio and Proportion - Discussion

Discussion Forum : Ratio and Proportion - General Questions (Q.No. 9)
9.
The sum of three numbers is 98. If the ratio of the first to second is 2 :3 and that of the second to the third is 5 : 8, then the second number is:
20
30
48
58
Answer: Option
Explanation:

Let the three parts be A, B, C. Then,

A : B = 2 : 3 and B : C = 5 : 8 = 5 x 3 : 8 x 3 = 3 : 24
5 5 5

A : B : C = 2 : 3 : 24 = 10 : 15 : 24
5

B = 98 x 15 = 30.
49

Discussion:
122 comments Page 11 of 13.

RISHIKESH said:   1 decade ago
Thanks alisha.

Murali said:   1 decade ago
If a:b:c=2:3:5 then the ratio of (b+c)/4:(c+a)/4:(a+b)/4 is?
Can any one give answer for this....

Ankur saxena said:   1 decade ago
a/b=2/3,b/c=5/8
a+b+c=98
2b/3+b+8b/5=98
b=30

Sweet said:   1 decade ago
Let a's amount= z
so b's amount=1210-z
now (4/15)z=(2/5)x(1210-z)
=>
(4/15)z=484-2/5z
=>
(4/15)z+(2/5)z=484
=>
by taking l.c.m (10/15)z=484
=> 10z=7260
=>
z=726

So a's amount=z=726

and b's amount=1210-726=484 ans.

Amit said:   1 decade ago
Hey thanks kalpa, its very easy to understand.

Vicky singh said:   1 decade ago
Thanks kalpa for solve such easy method to this question.

Avijeet said:   1 decade ago
Thanks alisha.

You used awesome shortcut:).

Emani Karthik Reddy said:   1 decade ago
Sum of numbers Ax+Bx+Cx=98->1
Ratio of first to second 2:3
second to third 5:8
the ratio A:B::C:D=2:3::5:8
find the ratio A:B:C
i.e A:B:C=2:3::(5*(3/5)):(8*(3/5)).
new ratio is 2:3::3:24/5
A:B:C=2:3:24/5
A:B:c=10:15:24
from 1 we get
10x+15x+24x=98
x=2
second number =15*2=30.

Alisha said:   1 decade ago
a+b+c=98
a/b=2/3 and b/c=5/8 and hence
a=2b/3 and c=8b/5
so,
2b/3+8b/5+b=98
34b+15b=98*15
49b=98*15
and finally, b=(98*15)/49=30

Ashok Sarkar said:   1 decade ago
Thanks kalpa it's very easy to understand


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